1. Field of the Invention
The present invention relates to a method and system for removing a metal contaminant deposited on a quartz member selected from the group consisting of a reaction tube, wafer boat, and heat-insulating cylinder of a vertical heat processing apparatus for a semiconductor process. The term “semiconductor process” used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or a glass substrate used for an FPD (Flat Panel Display), e.g., an LCD (Liquid Crystal Display), by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
2. Description of the Related Art
In recent years, owing to the demands of increased miniaturization of device patterns along with increased integration of semiconductor devices, it is required to adopt a narrower acceptable range of a contaminant deposited on a semiconductor wafer. Accordingly, before a quartz member, such as a reaction tube, wafer boat, or heat-insulating cylinder, is used in a vertical heat processing apparatus for a semiconductor process, cleaning is performed on the quartz member to remove contaminants, such as a metal contaminant, deposited on the quartz member.
When such cleaning is performed on a quartz member, DHF cleaning is adopted such that the quartz member is first cleaned by use of diluted hydrofluoric acid (DHF), which has been prepared by diluting hydrofluoric acid (HF) with purified water (DIW), and is then cleaned by use of purified water, for example. Jpn. Pat. Appln. KOKAI Publication No. 2006-188419 discloses a cleaning method in which a quartz glass tool or member is cleaned by use of an acid and is then cleaned by ultrasonic cleaning in a purified water set at 30 to 70° C. to remove metal contaminants.